Device for moving a watercraft

ABSTRACT

A device for moving a watercraft comprises: —at least one propulsion chamber having a first inlet section for a liquid, referred to as the upstream edge, and a second outlet section for the liquid, referred to as the downstream edge; at least one flexible membrane housed in the chamber; and at least one actuator configured to produce thrust from the watercraft through undulation of the membrane between the upstream edge and the downstream edge.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase entry under 35 U.S.C. § 371 of International Patent Application PCT/FR2020/051438, filed Aug. 5, 2020, designating the United States of America and published as International Patent Publication WO 2021/028635 A1 on Feb. 18, 2021, which claims the benefit under Article 8 of the Patent Cooperation Treaty to French Patent Application Serial No. 19 09105, filed Aug. 9, 2019.

TECHNICAL FIELD

The present description relates to the marine transport sector. More specifically, aspects of the present description relate to a device for moving a watercraft.

BACKGROUND

For decades, means of moving ships based on the principle of propulsion have been known. In particular, the propulsion of boats by way of one or more propellers has been known since the 1830s.

In general terms, a propulsion (or traction) propeller of a watercraft uses the action-reaction phenomenon to apply thrust to it. Thus, the propulsion of a ship is based on a rotational movement of a plurality of slats, called blades, distributed around a central axis of a propeller immersed in water, and arranged inside or outside of this ship.

In operation, the rotation of the blades results in the application of a force to the liquid on which the ship floats, the force being equal to and opposite the force applied by this liquid on the axis of the propeller, and therefore on the ship, with an intensity that is proportional to the mass of accelerated liquid.

Under the effect of the rotational movement of the propeller blades, a pressure difference is generated between the front and the rear of the propeller, this pressure difference causing movement of the liquid in the same direction, and therefore, by reaction, of the ship in the other direction.

However, and despite its widespread use, the propulsion of watercraft by way of a propeller has various drawbacks.

Firstly, the propeller motors used in the transport field have very low efficiencies. Rather than propelling water directly in a given direction, these motors tend to mix it in all directions.

In addition, such motors have a high fuel consumption, and, in particular, gasoline or diesel consumption. This consumption is even greater as the size and mass of the watercraft to be moved increases, which causes considerable environmental pollution. This pollution, for example, results from poor quality fuels, oil spills or degassing.

The environmental impact of known propeller motors also involves significant noise pollution, since they are generally noisy and disturb the underwater fauna and flora due to the significant and multidirectional mixing of liquid that they cause nearby.

In addition, known propeller motors pose significant safety problems due to the rotational movement of the blades, which can cause significant damage or even injury in accidents.

Furthermore, the handling of propeller motors is often costly due to the number and complexity of their mechanical parts, for example, the blades, crankshafts, reduction gears or even spark plugs that they comprise.

BRIEF SUMMARY

In order to improve the situation and to address this or these drawbacks, a general object of the present disclosure is to provide a propulsion device for a watercraft that respects the environment.

The propulsion device provided by the present disclosure also considerably reduces the risk of injury.

Furthermore, the propulsion device provided by the present disclosure is both compact and efficient.

In particular, a first object of the present disclosure relates, in general, to a device for moving a watercraft, the device comprising:

-   -   at least one propulsion chamber comprising a first inlet section         for a liquid, referred to as the upstream edge, and a second         outlet section for the liquid, referred to as the downstream         edge;     -   at least one flexible membrane housed in the chamber; and     -   at least one actuator configured to produce thrust of the device         through undulation of the membrane between the upstream edge and         the downstream edge.

Herein, the liquid considered is typically water, so that the described movement device applies directly to watercraft. However, it will be understood that this document also applies to devices allowing propulsive movement of vehicles in any type of liquid, for example, petroleum or gasoline.

Herein, a watercraft designates any type of floating or submersible vehicle adapted to move on a liquid and/or in this liquid, in particular, water. Such a vehicle can be partially or totally immersed in the liquid. This vehicle may be driven by any means on board, remotely, or independently.

Examples of floating watercraft include boats, whether motorized or not, such as sailboats, yachts, pleasure craft, rowing boats, marine drones, model craft, buoys, motorized watercraft, personal watercraft, rigid hull boats, semi-rigid boats (or zodiacs), inflatable canoes, water toys such as paddle boards, motorized platforms, water bikes, pedal boats, hydro-propelled lift vehicles, motorized surfboards on foils or not, submersible amphibious vehicles and transport vessels such as ferries, tankers, trawlers, cargo ships, barges or hovercraft.

Examples of submersible vehicles comprise any type of vehicle configured to operate underwater for prolonged periods. For example, a submersible vehicle may be a submarine, a torpedo, a submersible amphibious vehicle, a submersible drone, a remotely piloted underwater vehicle, a water toy such as a diving thruster, model submersible craft, or even a bathyscaphe.

The movement device allows mechanical power to be converted into hydraulic power, the power corresponding to the product of a flow rate and a pressure, for a given liquid.

In particular, the device for moving a watercraft allows the latter to be propelled relative to the liquid and in a direction opposite the displacement of the liquid in the propulsion chamber, by virtue of the thrust generated during the undulation of the membrane.

For example, a watercraft can be set in motion in forward or reverse gear.

Herein, the pressure differences produced between the upstream edge and the downstream edge of a propulsion chamber of a movement device according to any one of the embodiments described are typically on the order of a hundredth of a bar or tenths of a bar, but can also be on the order of a bar or several bars.

Preferably, when the membranes used are flexible elastomer membranes, these pressure differences are less than 16 bar.

In addition, the flow rates produced may vary depending on the properties and dimensions of the movement devices, propulsion chambers, flexible membranes and actuators used.

According to a specific example, the device comprises at least two propulsion chambers, for example, two, three or four propulsion chambers, each of the propulsion chambers comprising a first liquid inlet section, called the upstream edge, and a second outlet section of the liquid, called the downstream edge.

According to another specific example, the device comprises at least one propulsion chamber in which at least two flexible membranes are housed, for example, two, three or four flexible membranes.

According to yet another specific example, the device comprises at least two actuators, for example, two, three or four actuators, configured to generate a thrust of the device by undulation of at least one membrane between an upstream edge and a downstream edge of at least one propulsion chamber that the device comprises.

According to possible variants, the specific examples cited above can be considered alone or in combination.

According to a particular embodiment, the thrust is produced by the undulation of the membrane with a predetermined frequency and amplitude.

Herein, an undulation of a membrane may be understood as an alternation of a direction of movement of the membrane.

Advantageously, a particular choice of a frequency and an undulation amplitude for a given membrane allows the thrust generated and therefore the propulsion force of the movement device to be adjusted, which may be useful depending on the desired speed, the loading of the device, or even the environmental conditions in which the device operates, for example, the temperature, the swell or even the weather.

Herein, an undulation frequency of a membrane is typically greater than 0 hertz and less than 1,000 hertz, and preferably greater than 0 hertz and less than 200 hertz.

Herein, a peak-to-peak undulation amplitude of a membrane is typically less than half the length of this membrane between its upstream edge and its downstream edge, and preferably less than one fifth of the length of this membrane.

For example, it is advantageous to select an undulation frequency substantially equal, to within a few hertz, to a natural frequency or to a beat frequency of the membrane or of an actuator in order to transmit optimum power to the liquid when it is displaced in the device, or to reduce the vibrations produced when the latter is in operation.

Advantageously, the number of wavelengths between the upstream edge and the downstream edge is less than five undulations. For example, the number of wavelengths is less than one undulation in the case of stiff membranes allowing higher hydraulic powers than those of flexible membranes.

According to a particular example, the undulation comprises a movement of at least one end of the membrane by at least one actuator.

When at least one membrane housed in a propulsion chamber is made to oscillate by at least one actuator, a progressive wave is produced and propagates along the membrane. This progressive wave then causes the volume of liquid located in the propulsion chamber to be displaced, with a speed and direction substantially identical to those of the wave propagating through the membrane.

According to a particular example, the propulsion chamber comprises at least one volume, the volume being formed by at least one wall connecting the upstream edge and the downstream edge.

Herein, the wall(s) connecting the upstream edge and the downstream edge of a propulsion chamber are referred to as flanges. This or these flanges has or have the function of isolating the liquid being displaced inside the propulsion chamber from the rest of the device, which makes it possible to increase the pressure differential created by the undulation of the membrane in order to generate propulsion.

Preferably, the inlet and outlet sections are arranged, and may optionally be adjustable, in operation or not, so as to impart optimum thrust and speed to a vehicle comprising the device.

For example, the inlet and outlet sections are arranged to allow the attitude of the propulsion chamber or of the vehicle to be adjusted.

According to a particular example, the device comprises at least two propulsion chambers arranged in series or in parallel.

Herein, two propulsion chambers are said to be arranged in series when the downstream edge of one of the chambers is located substantially in alignment with the upstream edge of the other of the chambers. In particular, the downstream edge of one chamber can serve as the upstream edge of another chamber.

Two propulsion chambers are also said to be arranged in series when they are connected by a circuit, in particular, a hydraulic circuit, so that the fluid is directed from the downstream edge of the first chamber toward the upstream edge of the second chamber. Thus, two chambers arranged in series are not necessarily aligned geometrically.

Herein, two propulsion chambers are said to be arranged in parallel when the downstream edge and the upstream edge of one of the chambers is substantially parallel to the downstream edge of the other of the chambers and when the upstream edge of one of the chambers is substantially parallel to the upstream edge of the other of the chambers.

Two propulsion chambers are also said to be arranged in parallel when they are connected by a circuit, in particular, a hydraulic circuit, so that the fluid is directed from the upstream edges of the first and the second chambers toward the downstream edges of the first and second chambers.

In a particular case, two propulsion chambers arranged in parallel may have a common upstream edge and/or downstream edge.

Arranging several propulsion chambers in series, in parallel or according to other configurations in a movement device allows the thrust or the speed generated by the device, and therefore the thrust or the speed supplied to a watercraft comprising such a device, to be proportionally increased compared to a device that would comprise only a propulsion chamber.

Compared to a device comprising a single propulsion chamber, an example comprising several propulsion chambers arranged in parallel allows the flow rate to be increased for a pressure that varies little, which allows the thrust to be enhanced to the detriment of the speed.

As a variant, and with respect to a device comprising one propulsion chamber, an example comprising several propulsion chambers arranged in series allows the pressure to be increased for a flow rate that varies little, and therefore allows the speed to be enhanced to the detriment of the thrust.

When several flexible membranes are housed in the same chamber, this allows the thrust or the speed generated by the movement device to be increased without, however, considerably increasing the dimensions of this device.

According to a particular embodiment, at least two membranes housed in the same chamber undulate, owing to at least one actuator, with a phase shift by an angle chosen from a group comprising: an angle substantially equal to 0°, an angle substantially equal to 90°, an angle substantially equal to 180°, an angle substantially equal to 270°, and an angle substantially equal to 360° divided by the number of membranes in the chamber.

Herein, a phase shift angle substantially equal to another is an angle whose value is equal to the value of this other angle with an accuracy of plus or minus 10°, and preferably with an accuracy of plus or minus 5°.

Herein, two membranes that undulate with a phase shift of an angle substantially equal to 360°, equivalent to an angle substantially equal to 0°, are said to undulate in phase. Two membranes that undulate with a phase shift of an angle substantially equal to 180° are said to undulate in phase opposition.

Advantageously, and for example, when two membranes housed in two propulsion chambers, for example, two chambers in series, undulate in phase, such a configuration allows the liquid flowing through the two chambers to present greater laminarity and to reduce turbulence and therefore pressure drops by the movement device.

Advantageously, and for example, when two membranes arranged in two chambers in series undulate in phase opposition, this allows greater thrust to be provided.

In addition, an undulation of two membranes in phase opposition allows compensation for the imbalances due to the displacements of masses of liquid by these membranes, and to the masses of the moving parts of the actuator(s), since the first membrane undulates in a first direction and the second membrane undulates in a second direction, opposite the first direction.

Furthermore, operation in phase opposition allows an occlusion to be produced between the membranes, which allows the performance of the device to be increased.

When at least two membranes housed in the same chamber undulate with a phase shift of an angle substantially equal to 360° divided by the number of membranes in the chamber, these membranes are said to undulate in multi-phase mode, that is to say, the device comprises as many propulsion chambers as there are phases.

Two membranes, or more, can undulate, for example, with other phase shift values in order to promote particular movement modes or to reduce noise or vibrations produced by the operation of the movement device.

For example, it is possible to have three membranes housed in the same chamber and undulating relative to one another with a phase shift of 360° divided by three, i.e., 120°, thus providing a three-phase mode.

In the case of a movement device comprising three propulsion chambers and operating in three-phase mode, each propulsion chamber of this device comprises a membrane made to undulate with a phase shift of 360° divided by the number of phases, i.e., here three phases, to have a phase shift of 120°.

This allows such a device to be controlled with multi-phase electronics, for example, three-phase electronics, and also allows the vibrations to be reduced that propagate in the movement device, and therefore in a watercraft that would comprise such a device.

According to a particular embodiment, the at least one flexible membrane and the at least one actuator are configured to generate energy from a movement of the actuator by the flexible membrane.

Aside from the possibility of functioning as a means of propulsion, this allows the device to function as an energy generator.

It is thus possible, for example, to recover energy in order to recharge one or more batteries, or another energy retention means, when the device, and therefore the watercraft, has a speed difference relative to the liquid.

In this particular embodiment, at least one actuator can be connected to a membrane.

When the device, and therefore the propulsion chamber in which the membrane is housed, is stationary with respect to a liquid being displaced through the propulsion chamber, this liquid causes an undulation of the membrane(s) housed in the chamber due to the difference in speed between the chamber and the liquid. The undulation of the membrane then drives at least one actuator, which can then generate energy if it is connected to this membrane. This energy can be transformed into electricity to allow charging or recharging of batteries, for example.

Alternatively, the membrane can be constrained between its upstream and downstream edges, causing it to have undulations therebetween, which undulations increase the resistance of the membrane to fluid movement and therefore increase the power generated.

According to a particular embodiment, the upstream edge or the downstream edge comprises at least one liquid deflector.

This allows the movement direction of the device or of the thrust generated to be modified by choosing the orientation direction of each deflector with respect to the propulsion chamber.

This also allows the turbulence to be limited near the movement device and, in particular, near the upstream edge or the downstream edge of the at least one propulsion chamber.

At least one deflector is located close to at least one end of the membrane, allowing the liquid to be directed near the latter and turbulence to be limited in the propulsion chamber.

A second object of the present disclosure is to provide a watercraft comprising a hull and a movement device according to any one of the preceding objects and embodiments.

Advantageously, an intake and a discharge of the liquid take place respectively at the front of the zone where the movement device is located, and, in particular, of at least one propulsion chamber comprised by the movement device.

This intake and this discharge allow the watercraft to be propelled, and promote a specific movement direction based on the arrangement of the upstream edge and the downstream edge of the propulsion chamber(s) of the movement device relative to the orientation of the watercraft.

According to a particular embodiment of this second object covered by the present disclosure, a first element of the hull consists of the upstream edge of at least one propulsion chamber and a second element of the hull consists of the downstream edge of the propulsion chamber of the device.

Advantageously, an intake and a discharge of the liquid used to propel the watercraft take place respectively at the front of the zone where the movement device is located and at the rear of this zone, to promote a direction of this watercraft, when it requires preferential steering (normal operation in forward gear).

Advantageously, such movement devices allow a watercraft to be supplied with motor powers of less than 10,000 watts for model making, less than 40,000 watts for water toys, greater than 200 watts for pleasure craft, and greater than 100,000 watts for watercraft for transporting goods or people.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, details and advantages will appear on reading the detailed description below and on analyzing the accompanying drawings, in which:

FIG. 1 shows a schematic view of a movement device according to a first embodiment of the present disclosure;

FIG. 2 shows a schematic view of a movement device according to a second embodiment of the present disclosure;

FIG. 3 shows a schematic view of a movement device according to a third embodiment of the present disclosure;

FIGS. 4A and 4B show a perspective view and a vertical view of a movement device according to a fourth embodiment of the present disclosure;

FIG. 5 shows a schematic view of a movement device according to a fifth embodiment of the present disclosure;

FIGS. 6A and 6B show a perspective view and a vertical view of a movement device according to a sixth embodiment of the present disclosure;

FIG. 7 shows a schematic view of a movement device according to a seventh embodiment of the present disclosure;

FIG. 8 shows a schematic view of a movement device according to an eighth embodiment of the present disclosure;

FIG. 9 shows a schematic view of a movement device according to a ninth embodiment of the present disclosure;

FIG. 10 shows a schematic view of a movement device according to a tenth embodiment of the present disclosure;

FIGS. 11A-11C show different modes of operation of a movement device according to an eleventh embodiment of the present disclosure;

FIG. 12 shows a schematic view of a movement device according to a twelfth embodiment of the present disclosure;

FIG. 13 shows a schematic view of a movement device according to a thirteenth embodiment of the present disclosure;

FIG. 14 shows a perspective view of a watercraft comprising a movement device according to a fourteenth embodiment of the present disclosure;

FIGS. 15A and 15B show a perspective view of a watercraft comprising a movement device according to a fifteenth embodiment of the present disclosure, and a perspective view of a movement device comprised by this watercraft;

FIGS. 16A-16C show a perspective view, a perspective sectional view and a schematic sectional view of a movement device according to a sixteenth embodiment; and

FIGS. 17A-17C show a perspective view, a perspective sectional view and a schematic sectional view of a movement device according to a seventeenth embodiment.

Unless otherwise indicated, the elements that are common or similar to several figures bear the same reference signs and have identical or similar features, so that these common elements are generally not described again for the sake of simplicity.

DETAILED DESCRIPTION

For the most part, the drawings and the description below contain certain elements. They may therefore not only be used to better understand this disclosure, but also contribute to its definition, where applicable.

Reference is now made to FIG. 1, which shows a schematic view of a movement device 100 for a watercraft according to a first embodiment of the present disclosure.

As shown, the device 100 comprises a propulsion chamber 50 defining a cavity located between a first edge, referred to as upstream edge 50 a, and a second edge, referred to as downstream edge 50 b.

In operation, the device 100 is partially or completely immersed in a liquid, in particular, water, and is moving relative to this liquid with a given relative speed.

According to a variant of operation, the device 100 is not immersed, but at least part of a watercraft comprising the device is immersed and arranged to take in water.

For example, the device 100 may be moving at a first speed relative to a volume of water moving at another, second speed. The device 100 may thus move relative to a volume of water that is immobile or moving at any speed and in any direction.

Herein, the upstream edge 50 a is defined so as to correspond to the inlet section through which the water enters the propulsion chamber with a flow F1, and in general, the movement device.

Herein, the terms “flow” and “flow rate” are used equivalently.

Herein, the downstream edge 50 b is defined so as to correspond to the outlet section through which the water is evacuated out of the propulsion chamber with a flow F2, and in general, out of the movement device.

Herein, and non-limitingly, it will be understood that the movement of the device, and therefore of the propulsion chamber, can be reversed in operation so that the upstream edge 50 a then corresponds to the outlet section and so that the downstream edge 50 b corresponds to the inlet section.

In general, the propulsion chamber 50 is surrounded by two walls, called flanges 10 and 20, which can define various and varied profiles. The propulsion chamber 50 may also comprise at least one asperity.

Herein, a flange is generally a rigid wall, but non-limitingly, it may also be a flexible wall having a certain elasticity. For example, a flange defining a wall of a propulsion chamber may be a hull element of a watercraft, for example, a hull element of a boat.

For example, and as shown here, the flanges 10 and 20 are arranged so as to give the propulsion chamber 50 a convergent profile, that is to say, the section corresponding to the downstream edge 50 b has a surface smaller than the section corresponding to the upstream edge 50 a.

Non-limitingly, the flanges 10 and 20 may also be arranged so as to give the propulsion chamber 50 a divergent profile, that is to say, the section corresponding to the downstream edge 50 b has a surface greater than the section corresponding to the upstream edge 50 a.

The flanges 10 and 20 may also be arranged so as to give the propulsion chamber 50 a constant profile, that is to say, the section corresponding to the downstream edge 50 b has a surface substantially equal to the section corresponding to the upstream edge 50 a.

Advantageously, the convergent profile given to the chamber owing to the flanges 10 and 20 reinforces this pressure difference, and therefore increases the thrust generated by the undulation of the membrane M1 in the propulsion chamber, by displacement of the liquid from the upstream edge 50 a toward the downstream edge 50 b.

According to an example that is not shown, the movement device further comprises an additional part arranged close to the downstream edge of the propulsion chamber, outside the latter and in its alignment. This part has an inlet section substantially equal to the outlet section of the propulsion chamber. In this case, the part can act as a nozzle that is useful for steering and allows the speed of the exiting liquid, and therefore of a watercraft comprising the movement device comprising such an additional part, to be increased.

The device 100 further comprises a flexible membrane M1, the membrane being housed in the propulsion chamber 50 of the device 100.

Herein, and non-limitingly, a flexible membrane is any type of membrane arranged to oscillate with a predetermined amplitude and frequency. Such a flexible membrane may have a specific geometry, for example, rectangular, discoidal or tubular.

A flexible membrane preferably consists of a sheet of deformable material, elastic or not, a deformation of this membrane, for example, being able to be carried out at least in bending about an axis of the membrane.

As a variant, a flexible membrane is made of non-deformable material; the actuator is then designed to impart flexibility to the membrane, in particular, by allowing an offset of the actuated edge of the membrane.

According to different embodiments, a flexible membrane is profiled or not and comprises one or more materials, the materials possibly having different shapes, thicknesses and dimensions, variable from the upstream edge to the downstream edge, and characterized by different values of resistance, elastic limit, Young's modulus, shear modulus, Poisson's ratio, etc.

For example, a flexible membrane may be composed of a plurality of parts or lamellae hinged together, which may be directly or indirectly attached to a deformable structure.

Preferably, an attachment of the flexible membrane M1 is implemented at least at one attachment point P1, this attachment point P1 connecting the flexible membrane M1 to at least one actuator A1, for example, a mechanical movement device such as a piston, a connecting rod, or a magnetic or non-magnetic moving part.

Preferably, the housing of a flexible membrane in the chamber is implemented so that a first end of the membrane is located near the upstream edge of the chamber and a second end of the membrane is located near the downstream edge.

In general, the flexible membrane M1 has a leading edge, located near the upstream edge 50 a, and a trailing edge, located near the downstream edge 50 b.

When the membrane M1 is set in oscillation by the actuator A1, for example, from an attachment point P1 located near the leading edge, the flexible membrane M1 becomes the seat of a progressive wave that propagates along the membrane between the leading edge and the trailing edge.

According to one example, the characteristics of the flexible membrane, for example, its elasticity, its tension or even its dimensions, are chosen so as to guarantee that these optimize the speed of propagation of progressive waves in the volume of the membrane.

This undulation causes a deformation of the flexible membrane M1 according to a progressive wave that moves from a first edge of the membrane, here the edge of the membrane located near the attachment point P1, to a second edge, so that at least one point of the membrane situated between these two edges is driven by a transverse oscillating movement.

The coupling of the undulating membrane with the liquid in the chamber 50 creates a pressure field progressing with the progressive wave, thus producing a pressure difference between the upstream edge 50 a and the downstream edge 50 b. This results in a variation in the pressure of the liquid, expressed here by a variation in the speed of the incoming flow F1 to give a speed of the outgoing flow F2 of higher value.

Herein, a membrane may be defined by a given tension, for example, if its leading edge and/or its trailing edge is attached by a fastening means or an actuator. In this case, the tension of the membrane may exist in its state of rest or under the effect of a mechanical stress.

In particular, under the effect of a tension resulting from the application of two forces of opposite directions and applied to the leading edge and to the trailing edge of the membrane, an actuator may make it undulate, thus causing a wave to propagate in the membrane in the direction of the tension.

Herein, an actuator may be any type of actuation means.

According to different embodiments, an actuator may be chosen from: an electric motor, a heat engine, a nuclear engine, a hydrogen engine, a hybrid engine, a piezoelectric motor, or even a mechanical motor. The motor may provide motion similar to rotary, linear, or radial motion, and may comprise motion conversion parts to convert one motion to another.

According to different embodiments, an actuator may be powered by an energy source chosen from: an electric battery, an electric cell, a nuclear battery or cell, a fuel battery or cell, a hydrogen battery or cell, a photovoltaic panel, a fuel such as gasoline, diesel or a biofuel, or even a liquid fuel such as an alcohol, an ether or a hydrocarbon.

According to various embodiments, an actuator is driven mechanically or electronically. This driving may be done by way of power electronics allowing the movement of at least one membrane to be controlled, for example, by generating the appropriate signal in frequency, in force and/or in position for optimal propulsion according to the type of desired navigation, for example, depending on whether more or less thrust and speed is required for movement.

According to various embodiments, an actuator is controlled “instantaneously,” for example, by way of a signal comprising a high sampling frequency, or in an “average” manner, that is to say, by using the average of several periods of oscillation.

Advantageously, this allows impacts to be avoided between the membrane and the flanges in the event of air intake, due to the presence of, for example, bubbles or to a jump of the vehicle above a wave due to the weaker load. The movement can be electronically regulated in a closed loop.

In the case of an electrical actuation means, the current at its terminals may also be used to implement closed-loop control.

Advantageously, the position of at least one membrane may be determined by a sensor, for example, a sensor comprised by the device or the propulsion chamber, to help control the device.

Advantageously, an electronically controlled actuator allows at least one actuator to be driven with a sinusoidal movement to allow the membrane to oscillate sinusoidally. The electronic means used for control may also communicate with other instruments on board the watercraft that the device comprises, or that are located remotely.

In operation, the actuator A1 implements an alternating movement of the attachment point P1 in two opposite directions. One end of the membrane M1, here the end located close to the upstream edge 50 a of the propulsion chamber 50, is then moved alternately in a direction substantially transverse to the displacement of the water in the propulsion chamber 50.

Preferably, the attachment point P1 is located on or near one end of the membrane M1.

Preferably, the flexible membrane M1 is housed in the chamber 50 and connected to an actuator A1 by at least one attachment point located near the upstream edge 50 a or near the downstream edge 50 b.

As shown, the actuator A1 is located outside the propulsion chamber 50, in a sealed manner or not. Generally, however, an actuator connected to at least one flexible membrane housed in the chamber may be located inside the propulsion chamber 50, for example, between the flanges 10 and 20 or even inside one of these flanges.

Non-limitingly, at least one membrane, at least one propulsion chamber and at least one flange or a wall of the at least one propulsion chamber have various and varied geometries.

Three examples of geometry are described below.

According to a first example of geometry, an undulating membrane and/or at least one associated flange are defined by a rectangular or similar geometry, such as a trapezoid. In this case, the walls of the propulsion chamber may delimit a flat parallelepiped or tubular space, in which a rectangular membrane is arranged to be oscillated.

Advantageously, such a rectangular membrane is positioned in a plane parallel to the direction of movement of the liquid displaced in the propulsion chamber.

This allows provision of a movement device whose characteristics are suitable for a watercraft whose propulsion requires more thrust than speed, for example, for a pleasure or commercial craft, of the sailboat or motorboat type.

According to a second example of geometry, an undulating membrane and/or at least one associated flange are defined by a discoidal geometry. In this case, two coaxial walls can delimit the propulsion chamber, which then has the shape of a flattened cylinder or of a stack of layers. The undulating disc-shaped membrane is arranged to be oscillated between these walls.

Advantageously, such a disc-shaped membrane is positioned in a plane perpendicular to the direction of displacement of the liquid propelled into the propulsion chamber.

This allows provision of a movement device whose characteristics are suitable for a watercraft whose propulsion requires more speed than thrust, for example, for a personal watercraft or a jet-ski.

According to a third example of geometry, an undulating membrane and/or at least one associated flange are defined by a tubular geometry. In this case, the propulsion chamber can be delimited by two coaxial walls of revolution, between which the tubular undulating membrane is placed.

Depending on the type of geometry, the undulation of the membrane can take place in a parallel or transverse plane with respect to a main axis of the propulsion chamber and/or of the movement device itself. Regardless of the aforementioned geometries, however, the orientation of the plane in which the undulation takes place has no direct consequence with respect to the flow of the liquid.

If the membrane undulates in a plane transverse to the liquid flow, the resulting drag in the water will be greater.

Reference is now made to FIG. 2, which shows a schematic view of a movement device 110 for a watercraft according to a second embodiment of the present disclosure.

As shown, the device 110 comprises a propulsion chamber 51 in which two flexible membranes M1 and M2 are housed.

In the present case, the propulsion chamber 51 is formed by two substantially parallel flanges 11 and 21 defining a constant profile. A single actuator A1 is connected to the two membranes, which are aligned in a substantially parallel manner in the propulsion chamber 51. The propulsion chamber 51 has any upstream edge and any downstream edge, which are not necessarily aligned with the flanges 11 and 21.

According to an example that is not shown, at least one flange may be a sealed wall. Such a sealed wall may be split on either side of the membrane, which allows provision of two flanges, one upper and the other lower.

The upstream edge defines any inlet section through which the liquid enters the chamber with a flow F1, and the downstream edge defines any outlet section through which the water is discharged out of the chamber with a flow F2, and in general, out of the movement device.

Between the two membranes M1 and M2, an intermediate flange, called separator 31, is arranged that acts as a deflection means for the water flowing through the propulsion chamber 51. In the present case, the separator 31 has a profile such that it can be considered that the membranes M1 and M2 each undulate in a distinct and respective “sub-cavity,” the profile of which is convergent by the shape of the separator 31.

Advantageously, the separator 31 allows a reduction in the disturbances and the turbulence pressure drops resulting from the displacement of liquid located between the membranes M1 and M2.

In the present case, the separator 31 is placed so that the incoming water flow F1 separates into two components F11 and F12, the first of these components F11 corresponding to the part of the flow deflected toward the first membrane M1 and the second of these components F12 corresponding to the part of the flow deflected toward the second part of the flow.

At the outlet, a thrust is generated by the undulation of the two membranes M1 and M2, possibly in a synchronized manner.

Assuming an incompressible fluid, the flow rates are substantially identical when the sizes of the inlet and outlet sections are identical. Conversely, the pressures are higher at the thruster outlet. Thus, when the size of the outlet section is smaller, the pressures increase all the more, as does the fluid velocity, while the flow rate remains the same.

This allows provision of a compact movement device, comprising several membranes, and in which the outgoing flow F2 has a direction different from that of the incoming flow F1.

Reference is now made to FIG. 3, which shows a schematic view of a movement device 120 for a watercraft according to a third embodiment of the present disclosure.

As shown, the movement device 120 comprises a propulsion chamber 52 in which two flexible membranes M1 and M2 are housed, here arranged in series.

In the present case, the two membranes M1 and M2 are substantially aligned along the same overall axis in the propulsion chamber 52, this overall axis, for example, being aligned with the orientation of the flange 22, described below.

Each of the two membranes M1 and M2 is connected to one of the two actuators A1 and A2. The actuator A1, which is connected to the membrane M1 at an attachment point P11, is separate from the actuator A2, which is connected to the membrane M2 at another attachment point P12.

The movement device 120 thus comprises a single propulsion chamber 52, two membranes M1 and M2 housed in this chamber and two actuators A1 and A2 arranged to undulate the separate membranes M1 and M2, this undulation possibly being synchronized or not. The actuators may be either in phase or out of phase.

In the present case, the propulsion chamber 52 is formed by two flanges 12 and 22, the flange 12 having a sawtooth shape and the flange 22 having a substantially linear shape along an axis of the propulsion chamber 52.

The respective shapes of the flanges 12 and 22 are such that the membranes M1 and M2 each undulate in a respective sub-cavity of substantially convergent profile. In particular, the upstream edge and the downstream edge of the chamber 52 are substantially aligned with the flange 22, but not necessarily with the flange 12, which creates a progressive linear reduction in the section of each of these two sub-cavities between the upstream edge 52 a and the downstream edge 52 b of the propulsion chamber 52.

In operation, the undulation of the first membrane M1 by the first actuator A1 allows generation of an intermediate thrust of the liquid penetrating via the upstream edge with an incoming flow F1. This intermediate thrust corresponds to an intermediate flow F3, the liquid thus displaced by the first membrane M1 then reaching the second membrane M2, the undulation of which by the second actuator A2 allows an outgoing flow F2 to be obtained.

This allows the appearance of imbalances to be reduced in the event of a phase shift between the membranes. This also limits the vibrations in the device, and therefore the vibrations in a watercraft comprising this device.

In the present case, such a movement device allows a gain in pressure or flow rate to be provided compared to other devices, such as those described in the preceding figures. In particular, when several membranes are arranged in series, a pressure gain is obtained. When several membranes are arranged in parallel, a flow rate gain is obtained.

Advantageously, such a movement device also allows at least two membranes, housed in series and/or according to different configurations, to undulate while touching or without touching. At least two membranes can also undulate in phase or with a given phase shift.

Reference is now made to FIGS. 4A and 4B, which respectively show a perspective view and a vertical view of a movement device for a watercraft according to a fourth embodiment of the present disclosure.

As shown, the movement device 125 has a mode of operation substantially identical to that of the movement device 120, the latter comprising a single propulsion chamber in which two flexible membranes M1 and M2 are housed in series.

In particular, the propulsion chamber comprised by the movement device 125 has an upstream edge located near the leading edge of the first membrane M1, and a downstream edge located near the trailing edge of the second membrane M2. The trailing edge of the first membrane M1 is located near the leading edge of the second membrane M2.

In the present case, three actuators are configured to generate thrust from the movement device 125 by causing each membrane to undulate.

In particular, two actuators A11 and A12 are connected to the leading edge of the first membrane M1 and a single actuator A13 is connected to the trailing edge of M1. Similarly, two actuators A21 and A22 are connected to the leading edge of the second membrane M2 and a single actuator A23 is connected to the trailing edge of M2.

Preferably, the actuators A11 and A12 are synchronized with one another, and the actuators A21 and A22 are also synchronized with one another.

Advantageously, the synchronization between actuators may be such that the second membrane M2 extends the progressive wave of the first membrane M1.

If the membranes M1 and M2 are identical, they may undulate in phase by synchronizing the actuators A11 and A12 with the actuators A21 and A22, for example. Among other modes of operation, only one of the two membranes may be made to undulate, or both membranes may be made to undulate in phase opposition.

Among other possible modes of operation, a thrust reversal may be produced by the movement device 125, for example, to brake the device in a liquid. Such braking may be obtained, for example, by using only the actuators A13 and A23 to cause the membranes M1 and M2 to undulate.

FIG. 5 shows a schematic view of a movement device for a watercraft according to a fifth embodiment of the present disclosure.

In the present case, the movement device 130 comprises a single propulsion chamber, formed by two flanges 13 and 23, and in which two membranes M1 and M2 are housed in parallel.

As shown, an actuator A1 is used to cause the two membranes M1 and M2 to undulate simultaneously, synchronously or asynchronously, the two membranes not necessarily being aligned or of the same dimensions.

Unlike the second embodiment of the present disclosure as described previously, no separator is present in the propulsion chamber. This allows the two membranes M1 and M2 to touch or brush against one another during their respective undulations, thus creating a relative seal between them, and enabling space-saving regarding the separator in order to allow the passage of larger objects, for example.

FIGS. 6A and 6B show a perspective view and a vertical view of a movement device for a watercraft according to a sixth embodiment of the present disclosure.

In the present case, and similarly to the fifth embodiment described above, the movement device 135 comprises a single propulsion chamber in which two membranes M1 and M2 are housed in parallel.

Still in the present case, the two membranes M1 and M2 are rectangular in shape and housed one above the other, and each membrane may be made to undulate by at least one actuator.

Thus, undulation of the flexible membrane M1 may be obtained from its leading edge by way of the actuator A11 and/or A12, or at its trailing edge by way of the actuator A13.

Herein, the actuation of the upstream edge and of the downstream edge does not necessarily take place at the same time.

Similarly, undulation of the flexible membrane M2 may be obtained from its leading edge by way of the actuator A21 and/or A22, or at its trailing edge by way of the actuator A23.

FIG. 7 shows a schematic view of a movement device for a watercraft according to a seventh embodiment of the present disclosure.

In the present case, and similarly to the fifth embodiment described above, the movement device 140 comprises a single propulsion chamber 54, with no separator, in which two membranes M1 and M2 are housed in parallel.

The walls of the propulsion chamber 54 comprise two flanges 14 and 24.

Two separate actuators A1 and A2 are present here to undulate the flexible membranes M1 and M2, the actuator A1 being connected to the first membrane M1 by the attachment point P1 and the actuator A2 being connected to the second membrane M2 by the attachment point P2.

As a variant, the actuators A1 and A2 may be one and the same actuator, but comprising two moving parts that oscillate independently, in a synchronized manner, with a phase shift, or not.

In particular, the actuator A1 is located on the side of the flange 14 and the actuator A2 is located on the side of the flange 24, which makes it possible to isolate the two actuators.

Advantageously, one or the other of the actuators may be placed in a sealed chamber and, for example, makes it possible to undulate the membrane to which it is connected through a wall seal.

Herein, a sealed chamber is a chamber that is not in contact with the liquid propelled by the movement device. However, if the movement device is placed inside the watercraft, the actuator is not necessarily in a sealed chamber; it may, however, be sheltered from external environmental conditions, for example, bad weather.

Reference is now made to FIG. 8, which shows a schematic view of a movement device for a watercraft according to an eighth embodiment of the present disclosure.

In the present case, the movement device 150 comprises a single propulsion chamber 55, without a separator, in which three membranes M1, M2 and M3 are housed in parallel. The walls of the propulsion chamber 55 comprise two flanges 15 and 25. In an example that is not shown, it is also possible to provide four membranes, five membranes or more than five membranes in parallel.

As shown, one and the same actuator A1 is used to cause the three membranes M1, M2, and M3 to undulate simultaneously, synchronously or asynchronously, the three membranes not necessarily being aligned or of the same dimensions.

Reference is now made to FIG. 9, which shows a schematic view of a movement device for a watercraft according to a ninth embodiment of the present disclosure.

As shown, the device 160 comprises two propulsion chambers 56A and 56B, in each of which a flexible membrane M1 or M2 is housed.

Preferably, the two membranes are positioned in parallel planes.

The two chambers 56A and 56B are separated. For example, these may comprise a common flange, or may be separated from one another by a separator, the geometry of which, for example, allows the two chambers to be given a preferably convergent profile.

The upstream edge of the first chamber 56A acts as an inlet section for a first incoming flow F1 and the upstream edge of the second chamber 56B acts as an inlet section for a second incoming flow F3. The downstream edge of the first chamber 56A acts as an outlet section for a first outgoing flow F2 of liquid propelled by the membrane M1 from F1, and the downstream edge of the second chamber 56B acts as an outlet section for a second outgoing flow F4 of liquid propelled by the membrane M2 from F3.

At the outlet, a thrust is generated by the undulation of the two membranes M1 and M2, possibly in a synchronized manner, so as to provide a sum of outgoing flows F2 and F4 that is greater than the sum of the incoming flows F1 and F3 of entering water.

Advantageously, a single actuator A1 connects the two membranes M1 and M2, which are aligned substantially in parallel and along the same axis in each of the propulsion chambers 56A and 56B.

As described, the device for moving a watercraft 160 has an outlet section and a generated thrust that are increased, and in this case, increased in proportion to the number of propulsion chambers present, whereas a single actuator is sufficient to generate the thrust.

FIG. 10 shows a schematic view of a device for moving a watercraft according to a tenth embodiment of the present disclosure.

The movement device 170 comprises two propulsion chambers 57A and 57B of substantially constant profile, which are aligned in parallel and separated by a separator 32 in which two actuators A1 and A2 are located.

The chamber 57A comprises a flexible membrane M1 that is connected to the first actuator A1 and the chamber 57B comprises a flexible membrane M2 that is connected to the second actuator A2.

At the outlet, a thrust is generated by the undulation of the two membranes M1 and M2, possibly in a synchronized manner, so as to provide a total outgoing flow F2 that is greater than the sum of the incoming flows F11 and F12.

FIGS. 11A-11C show a device 180 for moving a watercraft according to an eleventh embodiment of the present disclosure.

In particular, each of FIGS. 11A, 11B and 11C illustrates a possible mode of operation of the device 180, which comprises a single propulsion chamber, a single flexible membrane M1 that is housed therein, and two actuators A1 and A2 connected to this same membrane.

The flanges of the propulsion chamber 58 here are arranged so as to give it a convergent profile. Non-limitingly, this profile may be divergent or constant according to other possible variants.

According to one example, a first actuator A1 is connected to the flexible membrane M1 at a first attachment point P11 that is located near its leading edge, and a second actuator A2 is connected to M1 at a second attachment point P21 that is located near its trailing edge.

In a case that is not shown, the actuator A1 and the actuator A2 may be one and the same actuator, with different possible attachment points to the membrane M1.

In other cases, the actuator A1 may be made up of part of the actuator A2, or vice versa. In general, more power supplied to undulate the leading edge of the membrane than the trailing edge promotes forward motion, while more power supplied to undulate the trailing edge rather than the leading edge of the membrane favors the reverse gear.

According to still other cases, the actuator of the upstream edge is the same as that of the downstream edge, but can actuate only one edge at a time.

This allows a means to be provided for controlling the outgoing flow F2 of the liquid propelled out of the chamber 58, following its displacement in the latter from the upstream edge toward the downstream edge.

For example, FIG. 11A illustrates a “normal” mode of operation, in which the membrane M1 is undulated by an alternating movement of the actuator A1 as previously described. When only the actuator A1 undulates M1, a thrust is generated from the upstream edge to the downstream edge in order to provide an outgoing flow F2 that is greater than the incoming flow F1.

In addition, this figure also makes it possible to illustrate a “reverse propulsion” mode of operation, in which the membrane M1 is undulated by an alternating movement of the actuator A2 only.

If the actuator A1 is stopped and if the actuator A2 is in operation, the waves propagating in the membrane M1 have an inverted direction of propagation, which allows displacement of the liquid from the downstream edge to the upstream edge. Indeed, when only the actuator A2 undulates M1, a thrust is generated from the downstream edge to the upstream edge in order to provide an outgoing flow that is greater than the incoming flow, and in directions opposite those shown here by F1 and F2.

When only the actuator A2 undulates the membrane M1, this allows the displacement direction of the liquid in the chamber 58 to be reversed, and therefore allows a watercraft that includes the device 180 to implement a reverse gear, without having to modify the orientation of the device or of the upstream edge of the chamber 58.

This therefore provides an advantageous means of thrust reversal, in particular, for wide watercraft, the movement device of which may be massive and the rotation of which may be all the more difficult to achieve.

In addition, this also makes it possible to illustrate a “synchronized” mode of operation in which the two actuators A1 and A2 contribute together to undulating the membrane M1.

This also allows provision of a motorization of the trailing edge of the flexible membrane M1, and therefore actuation of two of the edges of the undulating membrane, so that its undulation is conducive to specific modes of movement, for example, to limit noise and vibrations of the propulsion chamber, or of the membrane, which could touch the flanges during its undulation.

Advantageously, this actuating means also allows recovery of the energy from the downstream edge of the membrane M1 that has not been completely transmitted to the liquid, for example, when the watercraft comprising the device 180 moves forward, that is to say, when the actuator A1 is in operation, or even when the incoming flow F1 of liquid in the propulsion chamber is too great, so that the membrane M1, due to its characteristics, does not allow provision of a higher outgoing flow F2. This is the case, for example, when a watercraft comprising this movement device navigates on a watercourse with a high flow rate in the same direction, or for sailboats under sail and that have this device.

FIG. 11B illustrates a “zero propulsion”-type operating mode, in which the actuators A1 and A2 are used to position the membrane M1 along a flange of the propulsion chamber of the device 180, for example, by moving the leading edge and the trailing edge of M1 close to the same flange.

In the present case, and although this is not shown, a single actuator may also be provided to position M1. Indeed, if the upstream actuator is positioned near a flange without a second actuator being present, the other edge of the membrane will naturally tend to be placed on the side of the flange where the actuator positions it. A second actuator is therefore not essential in the present case.

In this case, no thrust is generated, since the membrane M1 is not made to undulate and is placed away from the flow of the liquid inside the chamber.

Advantageously, this placement apart allows the membrane to be shifted toward a flange in operation when the membrane undulates, and thus allows the membrane to be adjusted to an operation that suits it better.

Furthermore, this allows the membrane to be raised in order to allow, for example, the passage of a solid object present in the liquid, for example, pebbles, pieces of plastic or a piece of material, so as not to damage the membrane. Furthermore, if the watercraft has a movement means other than the present movement device, for example, a sail or a heat engine, this mode of operation allows the drag due to the membrane in the liquid to be reduced and limited.

It is thus possible to improve the durability of the membrane, and in general, of the movement device.

This allows the membrane M1 to be stretched without using attachment points or other tension means. The voltage may be adjusted, for example, by moving the actuator with respect to the membrane. This also makes it possible to limit the undulation amplitude of the membrane M1 and/or to prevent the latter from abutting against the flanges of the walls of the propulsion chamber 58.

FIG. 11C illustrates a “braking”-type operating mode, in which the actuators A1 and A2 are used to position the leading edge of M1 near a first flange and the trailing edge of M1 along another flange of the propulsion chamber of the device 180, for example, a flange that is opposite it.

This allows provision of active braking of a watercraft comprising the movement device, rather than using the friction between the vehicle and the liquid to reduce its speed, which requires more time to stop the watercraft. This braking is also gentler, since it simply increases the drag.

In particular, this positioning may be implemented so as to block, by way of M1, the flow of the liquid in the chamber, which closes the corresponding hydraulic circuit, such as a valve.

FIG. 12 shows a schematic view of a movement device according to a twelfth embodiment of the present disclosure.

In the present case, the movement device 190 comprises a propulsion chamber 59 of convergent profile, a flexible membrane M1 and an actuator A1 connected thereto.

Furthermore, the movement device 190 comprises three deflectors D11, D12 and D21. In particular, two of these deflectors, D11 and D12, are placed near the upstream edge of the chamber 59 and the third of these deflectors is placed near the downstream edge of the chamber 59. The deflectors D11 and D12 modify the direction of the incoming flow F1 while the deflector D21 modifies the direction of the outgoing flow F2.

When at least one deflector is placed near the upstream edge, an orientation of this deflector in a direction substantially parallel to a main axis of the propulsion chamber allows the liquid to be directed toward the first inlet section of the chamber, which increases the incoming flow rate.

As a variant, a deflector placed near the upstream edge and oriented in a substantially different direction from a main axis of the propulsion chamber makes it possible to avoid directing the liquid toward the first inlet section of the chamber, which reduces the incoming flow rate.

When at least one deflector is placed near the downstream edge, this makes it possible to direct the liquid at the outlet of the propulsion chamber, which modifies the direction of the thrust generated.

A deflector is, for example, a rudder that may be oriented in all directions, and preferably about an axis that is transverse with respect to the membrane in order to adjust the direction of the propelled liquid or along a parallel axis in order to adjust the inclination and/or the trim.

In order not to impede the flow of the fluid, the rudder may be next to the thruster, without being located in its flow. The deflector may also act as a wing or as a braking means such as flaps (or “foils”), in order to reduce or increase the drag of the watercraft.

According to various examples not shown, the movement device may comprise several horizontal and/or vertical deflectors. In particular, the movement device may comprise at least one deflector.

According to other examples, a deflector may be positioned near the middle of an inlet or outlet section, or on either side of an inlet or outlet section.

According to still other examples, the walls of the propulsion chamber may be oriented to direct the movement device in the liquid, which walls then serve as deflecting walls.

FIG. 13 shows a schematic view of a movement device according to a thirteenth embodiment of the present disclosure.

In the present case, the movement device 195 comprises a propulsion chamber 595 whose profile, defined by two flanges 19 and 29, is variable. The variability of the profile of the propulsion chamber 595 is made possible owing to the possible mobility of at least one flange, here the flange 29.

A flexible membrane M1 is housed in the propulsion chamber 595 and is connected to an actuator A1 by an attachment point P1.

The movement device 195 further comprises a second actuator A2 connected to the flange 29 by an attachment point P20, while the actuator A1 is further connected to this same flange 29 by an attachment point P10. The actuator A1 is thus connected both to the flexible membrane M1 and to the flange 29.

This allows the spacing of the flanges to be adjusted in order to modify the volume of the propulsion chamber, so as to adjust the thrust, the speed, the direction or the attitude of the watercraft. Such an adjustment may also be done manually, without an actuator, and/or when stopped.

Advantageously, the modification of the volume of a propulsion chamber may be implemented in a synchronized manner with the undulation of the flexible membrane M1. For example, an actuator A1 can move a leading edge or a trailing edge of a flexible membrane M1 simultaneously with the movement of a flange to which it is also connected.

According to various examples, several actuators may also be synchronized to move a flange of a propulsion chamber, simultaneously or not with the undulation of one or more membranes housed in this propulsion chamber.

According to an example that is not shown, at least one flexible membrane and at least one actuator are configured to generate energy from a movement of the actuator by the flexible membrane.

In such a case, the movement device functions as an energy generating device, the features of which nevertheless remain similar to the embodiments described above. The actuator, however, functions here as an electrical generating device. The flexible membrane is arranged in the propulsion chamber of the energy generating device, which therefore functions as an energy generating cavity and whose flanges delimit a duct for a flow of liquid moving between the upstream edge and the downstream edge of the chamber.

Also in such a case, operation as an electrical production device may be implemented automatically from a certain fluid flow speed or from the watercraft, for example, for speeds greater than 5 knots.

Advantageously, during this energy generating phase, the system may orient itself automatically so as to obtain the maximum possible generation.

In operation, the leading edge of the membrane M1 is subjected to a first voltage and the trailing edge of the membrane M1 is subjected to a second voltage of different values. Under the effect of the voltage difference, a flow of water circulating in the chamber causes the membrane M1 to undulate, and generates a wave propagation with a speed whose value depends on the resistance of the membrane M1 to the liquid flow, and therefore on the difference in voltage values.

Preferably, the membrane M1 is placed in a divergent part of the chamber of the device. This part is shaped to match the envelope of the amplitude of the waves during their progression in the membrane M1. The mechanical characteristics of the membrane are preferably chosen so that the wave propagation speed is always lower than the velocity of the liquid passing through the chamber.

FIG. 14 shows a perspective view of a watercraft according to another embodiment of the present disclosure.

In the present case, the watercraft 1000 is a boat comprising a semi-rigid hull 1100 and an outboard motor 1200, that is to say, a motor located outside the hull 1100.

In particular, the device 200 is attached to the rear of the watercraft 1000, and preferably to a transom.

Advantageously, the propulsion chambers that the device comprises may be placed in different positions and along a main axis of a watercraft, for example, along a roll axis, so that the thrust generated by all the propulsion chambers moves the watercraft in a straight line along this axis.

The motor 1200 here comprises a movement device 200 corresponding to any of the embodiments previously described.

In particular, and when the vehicle 1000 is on the water, it is possible to arrange the motor 1200 so that only the propulsion chamber(s) of the device 200 and the membrane(s) they comprise are immersed in the water, unlike actuators.

This motor may be steered by way of a rudder 1050 connected to the movement device 200 and may be used manually or electronically. This allows a relative rotation of the chamber with respect to the watercraft, for example, to save on an actuation means of the downstream edge by implementing a reverse gear through a complete rotation of the motor.

Furthermore, the relative height of the motor 1200 with respect to the water may be adjusted. This makes it possible to avoid damaging the propulsion chamber(s) of the device 200 when the depth of the water is shallow, or when the vehicle 1000 arrives on solid ground, such as a beach.

According to an example that is not shown, a motor comprising the device 200 may be attached to the vehicle 1000 by way of a flexible seal, for example, a seal of the collar type.

This makes it possible to avoid the transmission of vibrations to the watercraft, or at least to dampen the vibrations produced by the engine.

Such a configuration provides a watercraft that is simple, secure, and does not require significant transformation of the hull to accommodate the movement device.

FIGS. 15A and 15B show, respectively, a perspective view of a watercraft comprising a movement device and a perspective view of such a movement device, according to yet another embodiment of the present disclosure.

In FIG. 15A, the watercraft 2000 is a boat comprising a rigid hull 2100 and an inboard motor 2200, i.e., an engine located inside the hull 2100.

The motor 2200 comprises a movement device 300 corresponding to any of the embodiments previously described.

A first element 310 of the hull consists of the upstream edge of a propulsion chamber of the device 300 and a second element 320 of the hull consists of the downstream edge of the propulsion chamber.

According to one example, at least one of the upstream or downstream edges of a propulsion chamber of the device 300 is directly immersed in the liquid used for propulsion. Advantageously, this is the upstream edge, to avoid any priming problem. Furthermore, both the upstream edge and the downstream edge may be formed in the hull 2100 of the vehicle 2000, so that the inlet and the outlet of the propulsion chamber are located in the hull.

According to an example that is not shown, the hull of the watercraft may comprise a cant arranged so that the membrane and/or a flange of the propulsion chamber is partially or totally situated inside the hull.

For example, the upstream edge of the propulsion chamber of the device 300 may be arranged so as not to be directly immersed in the liquid. However, the device 300 may comprise a cavity immersed in the liquid used for propulsion, the latter connecting the propulsion chamber to the liquid.

Advantageously, this cavity may fill with liquid when the watercraft is launched, which improves the start-up of the movement device.

Advantageously, a downstream edge of at least one propulsion chamber of the device is immersed, and is preferably located at the rear of the watercraft when the latter has a preferential direction of movement, favoring optimum propulsion thereof.

According to one example, at least one of the edges among the upstream edge and the downstream edge of a propulsion chamber of the device 300 is connected to the liquid used for propulsion by a hydraulic circuit.

According to one example, the hull 2100 has at least one opening arranged to accommodate a hydraulic circuit. Preferably, this opening is located below the waterline of the vehicle 2000, immersed in the liquid. In addition, this opening may be located at the underwater hull of the vehicle 2000, underneath, on the sides, at the front as, for example, for the bow thrusters, at the rear, between two portions of its hull, or at an angle to its hull, so as to avoid any problem with priming the device 300.

Advantageously, the opening may be located at an inlet section or an outlet section of a propulsion chamber of the device 300, a propulsion chamber in which a membrane M1 is housed being located between the two, and at least one actuator of the device 300 being connected to this membrane by way of a sealed connection.

According to one example, the aforementioned hydraulic circuit may be arranged to promote laminar flow of the liquid in the movement device.

As a variant, the hydraulic circuit may be curved or bent, which saves space and simplifies installation of the movement device in the watercraft.

FIG. 15B shows a perspective view of the movement device 300.

The movement device 300 comprises a propulsion chamber 350 in which at least one membrane M1 is housed, the membrane being connected to two actuators A1 and A2.

The propulsion chamber 350 is of parallelepipedal geometry and is formed by two vertical rigid walls 301 and 302 as well as two horizontal rigid walls 310 and 320.

In the present case, the propulsion chamber 350 forms a sealed enclosure in the watercraft 2000. In particular, at least one rigid wall of this sealed enclosure acts as a flange for the propulsion chamber 350.

According to one example, at least the horizontal wall 310 acts as the upper flange of the propulsion chamber 350 while the horizontal wall 320 is a lower flange formed by a part attached to the vehicle hull. Ideally, this part is chosen and arranged in such a way as not to alter the tightness of the assembly.

According to another example, other rigid walls may be used as the upper, lower or lateral flange of the propulsion chamber 350.

According to yet another example, the propulsion chamber 350 is arranged so that the membrane M1 housed therein has only one flange facing one of its sides, which may be the hull itself.

Non-limitingly, the membrane M1 and/or the propulsion chamber 350 may not be of rectangular (or parallelepipedal) shape, but may match the shape of the hull, which makes it possible to limit any modification to be made to the watercraft during the installation of the movement device 300.

The actuator A1 or A2 may be arranged to move the membrane M1 via a connecting pin A10 or A20, the latter passing through at least one wall, for example, the wall 310.

In addition, at least one connecting pin may be provided with a seal, this seal possibly being an O-ring or a bellows, for example.

Although the propulsion chamber 350 may be a sealed chamber, the latter may be crossed by at least part of a hydraulic circuit containing the membrane M1. This configuration, for example, allows the actuator or some of its elements to be cooled owing to the liquid present in the chamber, such as its power electronics in the case of an electric motor.

According to an example that is not shown, the movement device 300 further comprises at least one bucket, located outside at least one propulsion chamber and near its downstream edge, and preferably outside the hull 2100 of the vehicle 2000, or outside the hull 1100 of the vehicle 1000.

This bucket is preferably a part arranged to push back the liquid leaving the downstream edge toward the upstream edge of the propulsion chamber, via the outside of the latter.

By discharging the outgoing flow of liquid from downstream to upstream, it is possible to reverse the direction of the thrust generated and therefore to allow reverse movement of the vehicle 2000.

When reversing, for example, the thrust generated causes a displacement of fluid toward the front of the vehicle, and the vehicle is propelled in the same direction as the displacement of the fluid in the propulsion chamber. This can be implemented by actuating at least one membrane located near the downstream edge of a propulsion chamber.

It is also possible to provide a variant in which the propulsion chamber and/or the bucket described above may be pivoted or rotated in order to modify the direction of the thrust generated by the movement device.

According to another example that is not shown, a propulsion chamber or a membrane of the movement device is arranged to be able to rotate with respect to an axis orthogonal to the direction of flow or propulsion of the liquid in the chamber. This rotation may be carried out inside the hull.

Advantageously, this allows the direction of the thrust generated by the movement device to be modified.

According to an example that is not shown, the movement device further comprises at least one noise reduction means or one mechanical damping means.

For example, the propulsion chamber(s) that comprise the movement device may be attached directly to the watercraft by way of anti-vibration feet.

Anti-vibration feet not only make it possible to improve the sealing of the motor, for example, when they have the form of a collar seal.

FIGS. 16A-16C illustrate a movement device 196 according to another embodiment.

As shown, FIGS. 16A, 16B, and 16C show a perspective view, a perspective cross-sectional view, and a schematic cross-sectional view of the device 196, respectively.

Preferably, the device is comprised in a cowling, the cowling, for example, having an asymmetrical NACA profile. The incoming flow F1 of liquid enters the device 196 via the upstream edge 51 a and the outgoing flow F2 is extracted from it via the downstream edge 51 b.

The device 196 comprises a propulsion chamber, a membrane M1 housed in this chamber, the membrane being made to undulate by an actuator A1.

The actuator is advantageously located directly beside the membrane, or in the water, upstream or downstream of the latter.

In the present example, the propulsion chamber has a tubular geometry, and the membrane M1 is of discoidal shape.

This configuration allows the pressure to be reduced near the upstream edge 51 a of the watercraft, and increased near the downstream edge 51 b.

In addition, the pressure is distributed more optimally around the periphery of the membrane.

FIGS. 17A-17C illustrate a movement device 197 according to yet another embodiment.

As shown, FIGS. 17A, 17B, and 17C represent a perspective view, a perspective cross-sectional view, and a schematic cross-sectional view of the device 197, respectively.

The device 197 comprises a propulsion chamber, a membrane M1 housed in this chamber, the membrane being made to undulate by an actuator A1.

In the present example, the membrane M1 is cylindrical. The membrane M1 surrounds an egg-shaped separator. Preferably, the propulsion chamber is cylindrical. 

1. A device for moving a watercraft, the device comprising: at least one propulsion chamber comprising a first inlet section for a liquid, referred to as the upstream edge and a second outlet section for the liquid, referred to as the downstream edge; at least one flexible membrane housed in the chamber; and at least one actuator configured to produce thrust of the watercraft through undulation of the membrane between the upstream edge and the downstream edge.
 2. The device of claim 1, wherein the at least one actuator is configured to undulate the membrane with a predetermined frequency and amplitude.
 3. The device of claim 1, wherein the at least one actuator is configured to move at least one end of the membrane to produce the undulation of the membrane.
 4. The device of claim 1, wherein the propulsion chamber comprises at least one volume, the volume being formed by at least one wall connecting the upstream edge and the downstream edge.
 5. The device of claim 1, further comprising at least two propulsion chambers arranged in series or in parallel.
 6. The device of claim 1, further comprising a plurality of flexible membranes housed in the same chamber.
 7. The device of claim 6, wherein at least two membranes of the plurality housed in the same chamber undulate with a phase shift by an angle chosen from a group consisting of: an angle substantially equal to 0°, an angle substantially equal to 90°, an angle substantially equal to 180°, an angle substantially equal to 270°, and an angle substantially equal to 360° divided by the number of membranes in the chamber.
 8. The device of claim 1, wherein the at least one flexible membrane and the at least one actuator are configured to generate energy from a movement of the actuator by the flexible membrane.
 9. The device of claim 1, wherein the upstream edge and/or the downstream edge comprises at least one liquid deflector.
 10. A watercraft, comprising: a hull; and a movement device, the movement device comprising: at least one propulsion chamber comprising a first inlet section for a liquid, referred to as the upstream edge and a second outlet section for the liquid, referred to as the downstream edge; at least one flexible membrane housed in the chamber; and at least one actuator configured to produce thrust of the watercraft through undulation of the membrane between the upstream edge and the downstream edge.
 11. The vehicle of claim 10, wherein the hull comprises: at least a first element comprising the upstream edge of at least one propulsion chamber; and at least a second element comprising the downstream edge of the at least one propulsion chamber.
 12. The device of claim 10, wherein the at least one actuator is configured to undulate the membrane with a predetermined frequency and amplitude.
 13. The device of claim 10, wherein the at least one actuator is configured to move at least one end of the membrane to produce the undulation of the membrane.
 14. The device of claim 10, wherein the propulsion chamber comprises at least one volume, the volume being formed by at least one wall connecting the upstream edge and the downstream edge.
 15. The device of claim 10, further comprising at least two propulsion chambers arranged in series or in parallel.
 16. The device of claim 10, further comprising a plurality of flexible membranes housed in the same chamber.
 17. The device of claim 16, wherein at least two membranes of the plurality housed in the same chamber undulate with a phase shift by an angle chosen from a group consisting of: an angle substantially equal to 0°, an angle substantially equal to 90°, an angle substantially equal to 180°, an angle substantially equal to 270°, and an angle substantially equal to 360° divided by the number of membranes in the chamber.
 18. The device of claim 10, wherein the at least one flexible membrane and the at least one actuator are configured to generate energy from a movement of the actuator by the flexible membrane.
 19. The device of claim 10, wherein the upstream edge and/or the downstream edge comprises at least one liquid deflector. 